Over the past 29 years Professor Olley has conducted research, both as a researcher and research manager, to improve our understanding of how large river systems respond to changes in land use and climate; in particular, where sediment and nutrients are derived. Progress towards this objective has involved developing and assessing new methods of tracing sediment and nutrients through catchments, as well as dating of fluvial sediments using innovative luminescence methods which he pioneered. He has broad experience in writing and editing, research policy and management, research communication, natural resources management, public participation, catchment management, research higher degree supervision, fluvial geomorphology, geochemistry, stable isotope and radioisotope chemistry, geology, optical dating, and riverine ecology. Authored and co-authored more than 100 scientific papers, 13 Conference papers and 26 Technical Reports in this or related fields. H index >25, Career ISI citations >2500, with 30 papers each exceeding 30, 7 exceeding 100; Three co-authored papers in Nature and two in Science.